The present invention relates to a housing for an electric component, such as a Gunn element, which is formed so as to surround electronic component.
For a distance radar in motor vehicles (ACC-adaptive cruise control) radar waves are used with frequencies about 50 gigahertz. For producing of these radar waves Gunn elements are utilized. They are composed of III-V-semiconductor material, such as GaAs or InP and produce a high frequency electromagnetic wave when a direct current is applied. The Gunn element has for example a diameter of 70 .mu.m and a thickness of 10 .mu.m and is contacted on its upper and lower side.
The typical construction of a Gunn oscillator is schematically shown in FIG. 5. A Gunn element accommodated in a housing 12 is arranged on an oscillator block 16 with integrated rectangular hollow conductors, and contacts with a direct current conductor 17 with HF choke and resonator disks. A frequency tuning pin 18 serves for the frequency tuning, while the power control is performed through a hollow conductor-short circuit slider 19.
The Gunn element is shown in FIG. 6a. The housing 12 of the Gunn element is located on a socket 9 of copper, which serves for the heat withdrawal and contacting of the contacts of the Gunn element. The housing 12 has a centering disk 11 of a conductive material, and the Gunn element abuts on it by means of a gold disk 2. A ceramic ring 4 is arranged around the centering disk 11 and isolates the socket 9 from the metallic cove 6. As mentioned, the element 1 contacts at the upper and lower side. While the lower side directly abuts on the gold disk 2 and is in contact with it, the connection to the conductive cover 6 is formed by a cross-shaped gold foil (Maltese cross 15). The gold foil is bonded in the center to the back contact of the component and at the edge of the upper metalization of the ceramic ring 4 which is in contact with the cover 6. By soldering of the cover 6 of metalized ceramics, a component 1 is hermetically closed in the housing 12.
Because of an intense heating, the Gunn element is subjected to a strong thermal expansion, for example shrinkage. This leads to a relative movement between the back side of the Gunn element 11 shown above in FIG. 6 and the cover 6. During a long term operation, this can lead to loosening of the bond contact, which is especially undesirable in components which operate for the vehicle safety.
Furthermore, the manufacture of the housing is expensive and complicated, in particular because of the bond process.